Oven control system and parts therefor on the like

ABSTRACT

A fuel control system for an oven having a source of fuel and main burner means. A pneumaticaly operated main valve is utilized for interconnecting the source to the burner when the main valve is actuated and for disconnecting the source from the main burner when the main valve is deactuated. A manually settable and thermostatically operated valve is provided for interconnecting a pneumatic control signal to the main valve to actuate the same when a temperature effect of the burner is below a set temperature effect and for disconnecting the pneumatic control signal from the main valve to deactuate the same when the temperature effect of the burner is above the set temperature effect, the thermostatically operated valve having a manually settable construction for controlling the cooking temperature effect of the burner and having a modifying construction for modifying the manually settable construction for controlling a burnoff cleaning temperature effect of the burner.

United States Paten Branson et al.

[ 51 May 28, 1974 [54] OVEN CONTROL SYSTEM AND PARTS THEREFOR ON THELIKE [75] Inventors: Charles I). Branson, Greensburg;

Francis S. Genbauffe, lrwin, both of Pa.

[73] Assignee: Rohertshaw Controls Company,

Richmond, Va.

[22] Filed: Sept. 15, 1972 [2]] Appl. No.: 289,285

Related US. Application Data [62] Division of Ser. No. 93,540, Novv 30,1970, Pat. No.

[52] US. Cl. 251/28 [51] Int. Cl. Fl6k 31/385 [58] Field of Search251/28 [56] References Cited UNITED STATES PATENTS 3,145,722 8/1964Mueller 251/28 X Primary Examiner-Arnold Rosenthal Attorney, Agent, orFirm-Candor, Candor & Tassone [57] ABSTRACT A fuel control system for anoven having a source of fuel and main burner means. A pneumaticalyoperated main valve is utilized for interconnecting the source to theburner when the main valve is actuated and for disconnecting the sourcefrom the main burner when the main valve is deactuated. A manuallysettable and thermostatically operated valve is provided forinterconnecting a pneumatic control signal to the main valve to actuatethe same when a temperature effect of the burner is below a settemperature effect and for disconnecting the pneumatic control signalfrom the main valve to deactuate the same when the temperature effect ofthe burner is above the set temperature effect, the thermostaticallyoperated valve having a manually settable construction for controllingthe cooking temperature effect of the burner and having a modifyingconstruction for modifying the manually settable construction forcontrolling a burnoff cleaning temperature effect of the burner.

5 Claims, 12 Drawing Figures PATENTEDwza mm SHEET 2 0F 8 BAKE ' BROILFIG.2

PATENTEDmmzs I974 SHEET 6 BF 8 y t PILOT BURNER OVEN CONTROL SYSTEM ANDPARTS THEREFOR ON THE LIKE This is a division of application Ser. No.93,540, filed Nov. 30, 1970, now US. Pat. No. 3,703,988.

This invention relates to a control system for an oven as well as toimproved parts for such a control system or the like.

One of the features of this invention is to provide a fuel controlsystem for an oven wherein the main control device is adapted to permitthe operation of the fuel control system for normal cooking operationsas well as for high temperature burn-off cleaning operations.

Another feature of this invention is to provide such a fuel controlsystem wherein both a bake burner means and a broil burner means aredisposed in the same oven cavity.

Another feature of this invention is to provide such a fuel controlsystem wherein only one of the burners is initially operated during aburn-off cleaning operation until after the temperature effect in theoven reaches a predetermined temperature below the burnoff temperatureat which predetermined temperature the other burner means is thenoperated simultaneously with the one burner means.

Another feature of this invention is to provide such a fuel controlsystem wherein once the burn-off cleaning temperature effect is producedin the oven, the control system cycles on and off only one of the burnermeans while providing continuous operation of the other burner means tomaintain the temperature in the oven at the burn-off cleaningtemperature.

Another feature of this invention is to provide improved controls forsuch control systems or the like.

In particular, one embodiment of this invention provides a fuel controlsystem for an oven that has a source of fuel and a main burner means,the control system including a pneumatically operated main valve meansfor interconnecting the source to the burner means when the main valvemeans is opened by the main valve means being actuated and fordisconnecting the source from the burner means when the main valve meansis closed by the main valve means being deactuated. A manually settableand thermostatically operated valve means is provided forinterconnecting a pneumatic control signal to the main valve means toactuate the same when the thermostatically operated valve means senses atemperature effect of the burner means below a set temperature effect ofthe thermostatically operated valve means and for disconnecting thepneumatic control signal from the main valve means to deactuate the samewhen the thermostatically operated valve means senses a temperatureeffect of the burner means above the set temperature effect. Thethermostatically operated valve means has manually settable means forcontrolling a cooking temperature effect of the burner means and hasmodifying means for modifying the manually settable means forcontrolling a burn-off cleaning temperature effect of the burner means.Such modifying means is also adapted to modify the manually settablemeans for controlling a warmth retaining and non-cooking temperatureeffect of the burner means. The modifying means can comprise a heatmotor.

Accordingly, it is an object of this invention to provide an improvedoven control system having one or more of the novel features set forthabove or hereinafter shown or described.

Another object of this invention is to provide an improved controldevice for such a control system or the like, the improved controldevice of this invention having one or more of the novel features setforth above or hereinafter shown or described. A

Other objects, uses and advantages of this invention are apparent from areading of this desciption which proceeds with reference to theaccompanying drawings forming a part thereof and wherein:

FIG. I is a schematic view illustrating one embodiment of the ovencontrol system of this invention.

FIG. 2 is a view similar to FIG. I and illustrates another embodiment ofthe fuel control system of this invention.

FIG. 3 is a view similar to FIG. I and illustrates another embodiment ofthe oven control system of this invention.

FIG. 4 is a view similar to FIG. I and illustrates another embodiment ofthe oven control system of this invention.

FIG. 5 is a schematic cross-sectional view illustrating an improvedcontrol device that is utilized in the oven control system of FIGS. 1-4.

FIG. 6 is a view similar to FIG. 5 and illustrates the control device ina keep warm setting position thereof.

FIG. 7 is a view similar to FIG. 5 and illustrates the control device ina burn-off oven cleaning position thereof.

FIG. 8 is a schematic cross-sectional view illustrating the main valvestructure utilized in the oven control system of FIGS. 1-4.

FIG. 9 is a view similar to FIG. 8 and illustrates an intermediateoperating position of the main valve means.

FIG. 10 is a view similar to FIG. 8 and illustrates the main valve meansin an open condition thereof.

FIG. 11 is a view similar to FIG. 8 and illustrates another embodimentof the main valve means of this invention.

FIG. 12 is a view similar to FIG. 11 and illustrates the main valvemeans of FIG. II in an open condition thereof.

While the various features of this invention are hereinafter describedand illustrated as being particularly adapted to provide control meansfor a fuel burning cooking apparatus, it is to be understood that thevarious features of this invention can be utilized singly or in anycombination thereof to provide control means for other devices asdesired.

Therefore, this invention is not to be limited to only the embodimentsillustrated in the drawings, because the drawings are merely utilized toillustrate some of the wide variety of uses of this invention.

Referring now to FIG. I, an improved oven control system of thisinvention is generally indicated by the reference numeral 20 andcomprises a fuel source manifold 21 having the conventional on-off valvemeans 22 therein, a main burner means 23, a main valve means 24 forinterconnecting the fuel source 21 by means of an inlet conduit means 25to an outlet conduit means 26 that leads to the main burner 23, a pilotburner means 27 being adapted to be continuously supplied fuel from theinlet conduit 25 through the main valve means 24 and to a conduit means28 leading to the pilot burner 27 so that the pilot burner 27 can ignitefuel issuing from the main burner means 23, a main control device 29 fordirecting a control signal from the source conduit by way of a conduit30 to a conduit means 31 that leads to the main valve means 24 so as toactuate the main valve means 24 and interconnect the inlet conduit 25with the outlet conduit 26 and for disconnecting that control signalfrom the main valve means 24 to cause the main valve means 24 todisconnect the inlet conduit 25 with the outlet conduit 26, a safetyvalve means 32 disposed in the control signal conduit 31 for preventingthe passage of a control signal therethrough unless a detector portion33 thereof detects the existence of flame means at the pilot burner 27,and a temperature sensing bulb 34 interconnected to an expandible andcontractible power element 35 of the main control device 29 by acapillary tube 36 whereby the temperature sensing bulb 34 senses theoutput temperature effect of the burner means 23 in the oven (not shown)utilizing the same.

In general, the main control device 29 of the control system 20 can bemanually set by the housewife or the like at any desired cookingtemperature and the same will cause the opening and closing of the mainvalve means 24 so as to cycle the main burner means 23 off and on tomaintain the temperature output effect of the oven at the selectedoutput temperature. In addition, the main control device 29 can be setat a high temperature burn-off cleaning operation position thereofwhereby the main control device 29 will cause the main valve means 24 tocycle on and off the main burner means 23 so as to produce a hightemperature burn-off cleaning temperature effect in the oven, such as900 F or the like.

The main control device 29 also includes means for automaticallymodifying the setting of the same to produce a warmth-retaining andnon-cooking temperature in the oven by cycling the main valve means 24to produce such warmth-retaining and non-cooking temperature in the ovenas will be apparent hereinafter. Of course, the control device can beinitially set for a warmth-retaining and non-cooking temperature, ifdesired.

Referring now to FIGS. 5, 6 and 7, the main control device 29 comprisesa housing means 37 containing a valve block portion 38 provided with avalve surface 39 interrupted by an inlet passage 40 that is adapted tobe interconnected to the conduit 30 of the control system 20 in anysuitable manner and leads to a chamber 41 in the valve block 38 that isadapted to be interconnected to another chamber 42 therein by a valveseat 43. The valve seat 43 is adapted to be opened and closed by a ballvalve 44 normally urged to an open position by a compression spring 45disposed in the chamber 42 whereby the compression spring 45 tends toforce the ball valve 44 against an end 46 of a stem 47 carried by amovable wall 48 of the power element 35 that has its threaded portion 49adjustably fixed to the housing means 37 in a conventional manner.

The chamber 42 in the valve block 82 is interconnected to a pair ofpassages 50 and 51 with the passage 50 leading to and interrupting thevalve surface 39 of the block 38 and with the passage 51 leading toanother chamber 52 in the valve block 38.

The chamber 52 in the valve block 38 is adapted to be interconnected toanother chamber 53 in the valve block 38 by a valve seat 54, the valveseat 54 being adapted to be opened and closed by a ball valve 55normally urged to an open position by a compression spring 56 disposedin the chamber 53 whereby the force of the compression spring 56 urgesthe ball valve 55 against an end 57 of a pin 58 having its other end 59engageable by a bimetal blade 60 of a modifying means 61 of the controldevice 29 carried by the housing means 37 thereof and in the embodimentillustrated in FIGS. 5-7 comprising a heat motor arrangement.

In particular, the heat motor arrangement 61 includes a heating coil 62for the bimetal blade 60 which has one end 63 thereof secured to thehousing means 37 and the other end 64 thereof free from the housingmeans 37 and being adapted to engage against the end 59 of the pin 58.When the blade 60 is unheated, the natural warp thereof tends to urgethe end 64 of the blade 60 to the left in FIG. 5 so as to continuouslybear against the pin 58 and overcome the force of the compression spring56 so as to maintain the ball 55 seated against the valve seat 54.However, when current is permitted to flow through the coil 62 which hasits opposed ends 65 and 66 respectively interconnected to externallyextending terminals 67 and 68, the heat produced by the coil 62 causesthe blade 60 to warp to the right in the manner illustrated in FIGS. 6and 7 to not only move the end 64 of the blade 60 away from the pin 58so as to permit the compression spring 53 to open the ball valve 55 awayfrom the valve seat 54, but also to carry therewith a latch member 69having one end 70 thereof pivoted to the housing means 37 by a pivot pin71 and the other end 72 thereof carrying a member 73 having an opening74 passing therethrough and receiving the blade 60 therethrough. Thelatch member 69 has a notch 75 therein and a cam surface 76 adjacent thenotch 75 for a purpose hereinafter described.

The chamber 53 in the valve block 38 is interconnected to a passage 77that also interrupts the valve surface 39 of the valve block 38. A valvemember 78 is disposed against the valve surface 39 and is illustrated inFIG. 5 as being a slide disc valve and schematically in FIG. 1 as beinga cock or plug valve. However, it is to be understood that the valvemember 78 can be of any desired configuration asthe purpose thereof ismerely to interconnect one of the passages 50 or 77 to the conduit 31while blocking the other of the passages 50 and 77 from the conduit 31.

For example, the control device 29 includes a control knob 79 secured ona control shaft 80 threaded into a threaded bore 81 of the valve block38 and being suitably interconnected to the valve member 78 by tyingmeans 82 or the like so that when the control knob 79 is disposed in anyon cooking position thereof, the passage 50 of the valve block 38 isinterconnected to the conduit 31 while the passage 77 is completelyblocked from the passage 31. However, when the control knob 79 is set ina burn-off cleaning temperature position thereof the tying means 82causes the valve member 78 to block the passage 50 from the conduit 31while interconnecting the passage 77 to the conduit 31 for a purposehereinafter described.

The control shaft 80 of the control device 29 has a disc 83 fixed at theend 84 thereof so that the axial position of the disc 83 in the housing37 is controlled by the threaded relation of the shaft 80 in thethreaded bore 81. A compression spring 85 has one end 86 bearing againstthe disc 83 and the other end 87 thereof bearing against an end 88 of alever 89 having its other end 911 receivable in the notch '75 of thelatch member 69 when the latch member 69 is disposed in the positionillustrated in FIG. 5. An intermediate portion 91 of the lever 89 bearsagainst a transverse pin 92 carried by the stem 47 of the power element35 whereby the force of the compression spring 35 and the force ofanother compression spring 93 disposed between the valve block 38 andthe end 911 of the lever 89, as well'as the force provided by the valvespring 15, tend to pivot the lever 89 in a clockwise direction about itspivoted end 90 in opposition to any downward movement of the movablewall 48 of the power element 35 for a purpose hereinafter described.

Another lever 94 is carried in the housing means 37 and has an end 95for pivoting on a fulcrum ledge 96 of the valve block 38 as acompression spring 97 is disposed between the valve block 38 and theother end 98 of the lever 94 to tend to pivot the same in a clockwisedirection about the pivot point 96. However, an intermediate portion 99of the lever 941 has an opening 11111 passing therethrough and receivingthe control shaft 89 whereby an embossment 191 of the intermediateportion 99 of the lever 94 bears against the disc 83 carried by theshaft 811 so that the disc 83 prevents the spring 97 from carrying thelever about the fulcrum point 96 until the disc 33 is moved upwardly asufficient distance as illustrated in FIG. 7 to cause the lever 94 toact against the lever 89 in a manner hereinafter described.

The fill for the temperature sensing bulb 34 capillary tube 36 and powerelement 35 can be an inert gas, such as helium, since the control device29 of this invention will respond to temperatures as high as 900 F andthe like.

The lever 89 when freed from the notch '75 of the latch member 69 in themanner illustrated in FiGS. ti and 7, is adapted to have end 83 engagedagainst a fulcrum embossment 102 on the housing means 37 by the force ofthe compression spring 85 so that the lever 89 will then pivot about thefulcrum point 1112 for a purpose hereinafter described.

The main valve means 2 1 for the control system 211 previously describedis illustrated in detail in FIGS. 8411 and will now be described.

As illustrated in FIG. 8., the main valve means 24 includes a housingmeans 1113 having an inlet 1114 for interconnecting to the inlet conduitand an outlet 1115 for coupling to the outlet conduit 26 with the inlet1114 being separate from the outlet 1115 by a valve seat 1116 projectinginto a chamber 107 of the housing means 103. A flexible diaphragm 1118is carried by the housing means 103 to define one side of the chamber1117 and separate the same from another chamber 1119 of the housingmeans 193, the flexible diaphragm 1118 carrying a rigid valve member orplate 1111 for opening and closing the valve seat 1116. A compressionspring 111 is disposed in the chamber 1119 to normally tend to urge thevalve member 1111 and its associated diaphragm 108 in a valve seatclosing direction.

Two other flexible diaphragms 112 and 113 are carried by the housingmeans 1113 with the diaphragm 113 cooperating with the housing means1113 to define a chamber 114 and in combination with the diaphragm 112 achamber 115 therebetween while the diaphragm 112 cooperates with thehousing 1113 to define another chamber 116.

The flexible diaphragm 113 carries a rigid backing member 117 carrying atubular extension 118 having an inwardly turned end 119 secured to aninner periphery 1211 of the diaphragm 112 that defines an opening 121passing centrally therethrough and being aligned with a resultingopening 122 at the turned end 119 of the tubular member 118. A ballvalve 123 is carried in the tubular extension 118 and is normally urgedby a compression spring 124 to seat against the opening 122 and closethe same, the tubular extension 118 having opening means 323 passingtherethrough to interconnect the interior of the tubular member 118 withthe chamber 115.

The housing 1113 has a wall portion 125 disposed between the chambers1119 and 116, the wall portion 125 having a tubular projection 126extending into the chamber 116 and defining a valve seat 127 at the openend thereof adapted to be opened and closed by the ball 123 since theprojection 126 is fully receivable into the openings 121 and 122 of thediaphragm 112 and extension 118 as fully illustrated in FIGS. 9 and 11).

A compression spring 128 is disposed in the chamber 116 to normally tendto urge the diaphragm 112 and, thus, the diaphragm 113 through thetubular extension 118 to the right in FIG. 8 so that the ball valvemember 123 is held away from the valve seat 127.

The chambers 1119 and 116 of the main valve means 24 are disposed influid communication with each other by openings 125 passing through theintermediate wall 125 of the housing 103.

The valve seat 127 of the tubular extension 126 of the wall 125 of thehousing 1113 is interconnected to a passage 129 formed in the housingmeans 103 and leading from the inlet 111 to an outlet passage 130 thatis interconnected to the conduit 28 leading to the pilot burner 27 asillustrated in FIG. 1, the flow of fuel through the passage 129 to theoutlet passage 130 being controlled by a suitable adjusting key 131 in aconventional manner.

The outlet passage 1311 is also interconnected to the intermediatechamber 115 through an orifice cup 132. In addition, the outlet passage130 is interconnected by another orifice cup 133 to a passage 1341- thatleads from a filter chamber 135 to the chamber 114. The filter chamber135 is adapted to be interconnected to the conduit 31 from the controldevice 29 as illustrated in FIG. 1 downstream from the safety valve 32.

Therefore, it can be seen that the control device 29 and main valvemeans 241 can be formed of relatively few parts in a relatively simplemanner to provide an oven control system 211 as illustrated in FIG. 1 aswell as the oven control systems illustrated in FIGS. 2-4 as will behereinafter described.

The safety valve 32 for the control system 20 illustrated in FIG. 1comprises a housing means 136 having an inlet chamber 137 interconnectedto the upstream part 138 of the conduit 31 while an outlet chamber 139thereof is interconnected to the downstream part 140 of the conduit 31,the chambers 137 and 139 being separated by a valve seat 141 adapted tobe opened and closed by a ball valve 142 normally urged to its closedposition by a compression spring 143 in the inlet chamber 137. However,an expansible and contractible power element 1441 is carried by thehousing means 136 and has a stem 1415 on the movable wall 146 thereofadapted to project through the valve seat 1411 and engage against thebail valve 142 so that when certain flames exist at the pilot burnermeans 27, the detector 33 causes the movable wall 146 of the powerelement 144 to move upwardly and thereby move the ball valve member 142away fromthe valve seat 141 as long as flames exist at the pilot burner27 so that the upstream part 138 of the conduit 31 will beinterconnected with the downstream part 140 thereof.

The detailed operation of the control system of FIG. 1 as well as theoperation of the control device 29 and the main valve member 24 will nowbe described.

Referring now to FIG. 1, and assuming that the control device 29 isturned to an off position, fuel is supplied to the pilot burner 27 tomaintain a flame at the pilot burner 27 since the conventional valve 22in the supply manifold 21 is in an on condition and fuel can therebyflow through the inlet conduit and passage means 129 and 130 of the mainvalve means 24 to the conduit 28 leading to the pilot burner 27. Thus,with flames at the pilot burner 27, the safety valve 32 has its ballvalve member 142 maintained away from the valve seat 141 so that theconduit means 31 between the control device 29 and the main valve means24 is in an open condition. However, since the control device 29 is inan off condition, the same is not directing any pneumatic signal throughthe conduit 30 to the main valve means 24 whereby the chamber 114 is atsubstantially atmospheric condition and the intermediate chamber 115 isalso at substantially atmospheric condition whereby the compressionspring 128 maintains the diaphragms 112 and 113 in the positionillustrated in FIG. 8 where the ball valve member 123 closes the opening122 of the tubular extension 118 and maintains the valve seat 127 of theprojection 126 is in an open condition for interconnecting the passage129 with the chamber 116 and, thus, with the chamber 109 through thewall openings 125 so that the fuel pressure on both sides of theflexible diaphragm 108 are equal. In this manner, the force of thecompression spring 111 maintains the valve member 110 against the valveseat 106 so that no fuel can flow from the inlet conduit 25 to theoutlet conduit 26 and, thus, to the main burner means 23.

However, when the control knob 79 of the control device 29 is moved fromits off position to any selected on cooking position thereof, the samecauses the valve member 78 to unblock the passage 50 and interconnectthe passage 50 to the upstream part 138 of the conduit 31 and at thesame time axially adjust the control shaft 80 relative to the housing 37so that the force of the compression spring 85 tending to pivot thelever 89 in a clockwise direction about the pivot point 92 is added tothe force of the compression springs 93 and against the transverse pin92 of the stem 47 of the movable wall 48 of the power element 35 so thatthe temperature of the oven must increase to the set temperature of theselector knob 79 in order to cause the power element 35 to expand inopposition to the force setting of the spring 85 and move the ballmember 44 against the valve seat 43.

However, since the temperature of the oven is normally below thetemperature setting of the knob 79 when the same is first turned to anon cooking position thereof, the ball valve member 44 is in the openposition as illustrated in FIG. 5 whereby a fuel source pneumatic signalis adapted to flow from the conduit 30, passage 40, open valve seat 43,and passage 50 into the control signal conduit 31 and since the safetyvalve 32 is in an open position, into the chamber 114 of the main valvemeans 24 to pressurize the chamber 114 and thereby cause the diaphragm113 to move to the left as illustrated in FIG. 9 carrying therewith thediaphragm 112 until the ball valve member engages against the valve seat127. In this manner, further movement of the ball valve member 123 tothe left is prevented even though the diaphragms 113 and 112 can furthermove to the left from the position illustrated in FIG. 9 to the positionillustrated in FIG. 10. As the diaphragms 113 and 112 continue to moveto the left from the position illustrated in FIG. 9 to the positionillustrated in FIG. 10, it can be seen that the tubular extension 118carried by the diaphragm 1l3now moves away from the ball valve member123 so that the intermediate chamber 116 and, thus, the chamber 109,through the wall openings is now interconnected to the tubular extension118 and through the openings 323 in the tubular extension 118 to thechamber 115 which is vented to the pilot burner outlet through theorifice cup 102 which has an orifice therein larger than the orifice ofthe orifice cup 133. This reduction in pressure on the spring side ofthe diaphragm 108 causes the diaphragm 108 to move away from the valveseat 106 as illustrated in FIG. 10 and since the escape of gas pressurefrom the intermediate chamber 116 is increased as the opening betweenthe ball valve member 123 and valve seat 122 becomes greater, the sameresults in the diaphragm 108 moving to an open position at a rapid rateto provide substantially a snap opening movement thereof whereby fuel isnow permitted to flow from the inlet 104 to the outlet 105 of the mainvalve means 24 and, thus, to the burner 23 to be ignited by the pilotburner 27. Thus, as long as the temperature of the oven is below thetemperature effect setting of the control knob 79, the ball valve 44 ofthe control device 29 is in an open position so that the pneumaticsignal is continuously directed to the chamber 114 of the main valvemeans 24 to maintain the same in the open position as illustrated inFIG. 10.

However, when the temperature in the oven reaches or slightly exceedsthe temperature setting of the control knob 79 of the control device 29,the expansion of the fluid in the temperature sensing bulb 34 is suchthat the same has caused the movable wall 48 of the power element 35 tomove downwardly in FIG. 5 in opposition to the force of the compressionsprings 85, 93 and 45 a distance sufficient to seat the ball valvemember 44 against the valve seat 43 and thereby terminate the flow ofcontrol signal fuel to the conduit 31 and, thus, to the chamber 114 ofthe main valve means 24. Since no more pressure is being directed to thechamber 114 of the main valve means 24, the pressure in the chamber 114bleeds through the orifice cup 133 to the pilot burner 27. As thepressure in the chamber 114 is reduced, the diaphragm 113 moves to theright under the force of the compression spring 128 and subsequently thevalve seat 122 makes contact withthe ball valve 123 to carry the same tothe right and thereby off of the valve seat 127. Movement of the ballvalve 123 off of the valve seat 127 again permits the chambers 116 and109 to have fuel under pressure directed therein by the passage 129 sothat the pressure across the diaphragm 108 subsequently equalizes andthe compression spring 111 can again move the diaphragm 108 to its valveclosing position as illustrated in FIG. 8 to terminate the flow of fuelto the main burner means 23.

Thus, the main control device 29 cycles the control signal to the mainvalve means 24 to cause the main valve means 24 to cycle the main burnermeans 23 between its off and on conditions to tend to maintain thetemperature in the oven at the temperature selected by the control knob79.

If the heat motor means 61 is interconnected to a meat probe or timer insuch a manner that after the oven has been operating at the selectedcooking temperature of the control knob 79 for a preselected time periodor for a preselected meat probe condition of the food being cooked bythe oven, the coil 62 can be automatically energized to heat the bimetalmember 60 and cause the same to warp to the right as illustrated in FIG.6 carrying the latch member 69 therewith which frees the end 90 of thelever 89 so that the force of the compression spring 85 can now pivotthe lever 89 on the transverse pin 92 and engage the end 88 of the lever89 against the fulcrum point 102 on the housing means 37 so that now theforce of the compression spring 93 is imposed on a long moment arm ofthe lever 89 to oppose downward movement of the movable .wall 48 of thepower element 35 whereby the power element 35 will now tend to maintainthe oven temperature at a warmth retaining and non-cooking temperaturein the manner previously described by opening and closing the ball valvemember 44. Should the heat motor 61 only be momentarily energized tocause such rightward movement of the blade 60 and latch member 69 toprovide the keep warm operation of the control device 29, a rewarping ofthe blade 60 back to the left even though causing a closing of the ballvalve member 55 against the valve seat 54 will not effect the operationof the control device 29 as only the passage 50 is opened by the valvemember 78 in any cooking position of the valve 79 or in the keep warmposition thereof.

Of course, if a keep warm temperature is initially selected by thehousewife or the like the heat motor 61 is immediately energized so thatthe control device 29 will initially assume the condition illustrated inFIG. 6.

When it is desired to utilize the ovencontrol system of this inventionfor an oven cleaning operation wherein the temperature effect is to bemaintained at a relatively high temperature, such as 900 F. for burningoff the soilage inside the oven, the control knob 79 of the controldevice 29 is set in an oven cleaning position thereof which not onlycauses the valve member 78 to block the passage 50 and open the passage77 to the conduit 31, but also the control knob 79 has caused thecontrol shaft 80 to be threaded into the valve block 38 a distancesufficient to cause the intermediate portion of the lever 90 to bearagainst the intermediate portion of the lever 89 as illustrated in FIG.7 so that the force of the compression spring 97 will be added to thelever arrangement 89 in opposing downward movement of the movable wall48 of the power element 35.

Also, through a suitable electric switch (not shown), the control knob79 when set in an oven cleaning position and through suitableinterlocks, such as the locking of the oven door, will cause the heatmotor 61 to be engaged so that the bimetal member 60 warps to the rightas illustrated in FIG. 7 to unlatch the end 90 of the lever 89 from thelatch member 69 whereby the end 88 of the lever 89 is now acting againstthe fulcrum point 102 of the housing means 37. In this manner, the forceof the compression spring 93 and the compression spring 97 as well asthe spring 45 is opposing downward movement of the movable part 48 ofthe power element 35. Thus, the heat motor 61 must remain energizedduring the entire oven cleaning operation so as to maintain the ballvalve member in the open condition as illustrated in FIG. 7 whereby theopening and closing of the ball valve member 44 by the power element 35will control the main burner 23 in the manner previously describedexcept that the same will be maintaining a burn-off cleaning temperaturein the oven, the control signal from the control device 29 to the mainvalve means 24 being through the'open valve seat 54 and passage 77 underthe control of the ball valve member 44.

' When the, burn-off cleaning operation is terminated, the energizing ofthe heat motor 61 is also terminated and if the control knob 79 has notbeen turned back to the off position thereof, the lever 69 will tend tomove back to the right but will be opposed by the end 90 of the lever89. However, the bimetal member can warp to the left to engage againstthe pin 58 and thereby close the ball valve member 55 against the seat54 so that no more fuel can be delivered to the actuation chamber 114 ofthe main valve means 24.. Thus, the operation of the main burner 23 isterminated. As the oven cools down, the end 90 of the lever 89 will camdown along the cam surface 76 of the latch member 69 to be subsequentlyreceived in the notch thereof and thereby permit the latch member 69 toassume the position illustrated in FIG. 5 and thereby latch the end ofthe lever 89 so that the control knob 79 can beutilized to subsequentlyset the control device 29 in a cooking position thereof withoutrequiring a resetting action by the housewife after an oven cleaningoperation.

Therefore, it can be seen that the control device 29 and the main valvemeans 24 of this invention can be utilized in the fuel control system 20to not only control the burner means 23 for a cooking and/or keep warmoperation thereof, but also for a burn-off cleaning operation in asimple and effective manner.

However, such control device 29 and main valve means 24 can also be usedin other oven control systems of this invention.

For example, reference is now made to FIG. 2 wherein another controlsystem of this invention is generally indicated by the reference numeral150, the control system including the control device 29A of thisinvention and two main valves 24A and 24B respectively for controllingthe flow of fuel from inlet conduit means 25A and 25B leading from thesource conduit 21A respectively to a bake burner 151 and a broil burner152.

Thus, the control system 150 is being utilized for a double burner,single cavity oven and is adapted to operate either the bake burner, thebroil burner or both the bake burner 151 and broil burner 152 for anoven clean off operation as will be apparent hereinafter.

Each main valve 24A and 24B continuously supplies the fuel in the mannerpreviously described to the pilot burner means 27A and 27B respectivelyutilized for the and 318 leading from the control device 29A to theoperating chambers 114A and 1148 of the main valve means 24A and 243.

The valve member 78A for the control device 29A is so constructed andarranged that when the control knob (not shown) of the control device29A is set for a baking operation, only the outlet 50A of the control'device 29A is interconnected to the conduit 31A whereby the main valvemeans 24A will operate the bake burner 151 in the manner previouslydescribed to maintain a selected baking temperature effect in the oven.When the valve member 78A is set in a broil position, only the outlet50A of the control device 29A is interconnected to the conduit 31Bwhereby the main valve means 24B controls the broil burner 152 in themanner previously described.

When the control knob of the control device 29A is set in an ovencleaning position, the valve member 78A is so constructed and arrangedthat the same only interconnects the outlet 77A to both conduits 31A and318 so that both the bake burner 151 and broil burner 152 will beoperated to produce the self cleaning tempera ture effect by the controldevice 29A as previously described.

Another oven control system of this invention is generally indicated bythe reference numeral 153 in FIG. 3 and also comprises a single controldevice 29C and two main valve means 24C and 24D respectively controllingthe flow of fuel to a bake burner 151C and to a broil burner 152D in amanner substantially similar to the control system 150 previouslydescribed when the control device 29C is being utilized for a baking orbroiling operation.

However, for a cleaning operation of the control system 153, the valvemember 78C is so constructed and arranged that when the same is set inan oven cleaning position thereof, the same interconnects the outlet 77Cto the control signal conduit 31D for operating the broil burner 152D inthe manner previously described and also interconnects the outlet 77C toa control signal conduit 154 that leads to a temperature responsivevalve means 155 that has an outlet 156 interconnected to the controlsignal conduit 31C for the bake burner valve means 24C in advance of thesafety valve 32C thereof.

The temperature responsive valve 155 comprises a housing 157 having twospaced valve seats 158 and 159 having a movable ball valve member 160disposed therebetween and normally urged to the left in a closedposition against the valve seat 158 by a compression spring 160'. Atemperature responsive power element 161 is provided with a stem 163adapted to project through the valve seat 158 and engage the ball valvemember 160, the power element 161 being interconnected by a capillarytube 262 to a temperature sensing bulb 263 that senses the temperaturein the oven.

The temperature responsive valve means 155 is so constructed andarranged that when the control device 29C is set for a burn-off cleaningoperation, the ball valve member 160 remains in its closed positionagainst the valve seat 158 until the operation of the broil burner 152Dunder the control of the control device 29C has raised the temperatureof the oven to a predetermined temperature that is below the desiredburn off cleaning temperature. When the predetermined temperature isreached, the power element 161 has moved the ball valve member 160intermediate the valve seats 158 and 159 so that the control signal fromthe control device 29C will now be directed to the valve means 24C foroperating the bake burner 151C simultaneously with the broil burner151D. However, when the temperature in the oven subsequently reaches thepredetermined clean off temperature, the power element 161 of the valvemeans has expanded in such a manner that the same will close the ballvalve member against the valve seat 159 and thereby terminate theoperation of the bake burner 151C. Thus, the temperature responsivevalve 155 will cycle the bake burner 151C between its off and onconditions to tend to maintain the oven at the burn off cleaningtemperature as the broil burner 152D will be continuously operatedduring the oven cleaning cycle.

However, during a runaway condition of the oven above the cleaningtemperature, the control device 29C will terminate the flow of fuel tothe outlet 77C thereof by the ball valve member 55C in the mannerpreviously described whereby the thermostatic device 29C will act as ahigh limit should the valve means 155 fail.

Another oven control system of this invention is generally indicated bythe reference numeral 164 in FIG. 4 and is substantially identical tothe control system 153 previously described except that such controlsystem 164 is for a muffle type oven wherein an air supply means 165must be continuously operating during the use of the bake burner 151Eand/or use of the broil burner 152F.

The passage 129E of the main valve means 24E is directly interconnectedto the conduit 28E leading to the pilot burner 27E for the bake burner151E whereas the passage 130E of the valve means 2413 is interconnectedto a conduit 165E that leads to another small burner 166E adjacent thepilot burner 27E so that if any fuel issues from the burner 166E in themanner hereinafter described, the same will be ignited by thecontinuously burning pilot burner 27E.

Similarly, the main valve means 24F for the broil burner 152F has itspassage 130F interconnected to a conduit 165F that leads to a smallburner 166F disposed adjacent the pilot burner 27F for the broil burner152F. However, the pilot burner 27F for the broil burner 152F isinterconnected by a conduit 167 to the valve means 78F of the controldevice 29F.

The main control device 29F is similar to the control device 29previously described except that the heat motor means 61F thereof isonly utilized for modifying the lever arrangement therein when energizedin the manner previously described as no ball valve equivalent to theball valve 55 is provided in the thermostatic device 29F.

A pair of air sensing valves 168E and 168F are provided respectively forthe burners 151E and l52F, each air sensing valve 168E and 168Fcomprising a housing means 169 having a flexible diaphragm 170 dividingthe same into two chambers 171 and 172 with the chamber 172 beinginterconnected to a branch conduit 173 by a valve seat 174 adapted to beopened and closed by a ball valve member 175 carried by the diaphragm170 and normally being urged in an open position by a compression spring176. However, the chamber 171 of each air sensor 168E and 168F isintercon nected to a conduit means 177 interconnected to the outlet 178of the air supply 165 so that when the air supply is operating, the samepressurizes the chambers 171 to cause the diaphragms 1711 to move theball valve members 175 fully against the valve seats 174 in the mannerillustrated in FIG. 4.

The pneumatic control signal conduits 31E and 31F respectively have thesafety valves 32E and 32F therein except that the downstream parts 14015and 14F thereof have branch conduits 179E and 1791 respectively leadingto the chambers 172 of the air sensors 168E and 1681 The branch conduits173 of the air sensors 168E and 168F are respectively interconnected tothe conduits 165E and 165F that lead to the auxiliary burners 166E and16oF for a purpose now to be described.

Should pneumatic signals be directed through the conduits 31E and 31Ftoward the main valve means 24E and 24F and the air supply 165 not beoperating, then the ball valve members 175 of the air sensors 168E and1681 will be in an open position so that the pneumatic signal passingthrough the open safety valves 32E and 32? will be diverted through theair sensors 16815 and 168F to the burners 166E and 166F to be ignitedand burn without causing opening of the main valves 24B and 24F.However, should the air supply 165 be operating, then the ball valvemembers 175 will be closed against the valve seats 174 in the airsensors 168E and 168F so that the control signal will only be directedto the main valves 24E and 24F to open the same in the manner previouslydescribed The outlet 50F of the control device 29F in combination withthe valve member 78F is so constructed and arranged that when the valvemember 78F is set in a broiling or oven cleaning position, the inlet 40Ffrom the supply conduit 25F is directly connected to the conduit 167leading to the pilot burner 27F for the broil burner 152F with thecontrol device 29F operating suitable ignition means (not shown) forigniting the pilot burner 27F. Also, when the valve member 78F is set ina baking position, the outlet 50F is directly connected to the conduit31E to operate the bake burner 1515 in the manner previously described.

However, the valve member 78F also controls the interconnection to twoconduit means 180 and 181 so that when the valve member 78F is set in abroiling or self cleaning position, the outlet 50F is interconnected tothe conduit 180 and when the valve member 78F is set in an oven cleaningposition, the valve member 78F interconnects the conduit 181 to theconduit 31E.

The conduits 180 and 181 are also interconnected to a temperatureresponsive valve 155F similar to the valve 155 of FIG. 3 except that theconduit 180 is interconnected to the spacing between the valve seats158F and 159F with the conduit 181 being interconnected to the left ofthe valve seat 158F and the conduit 31F being interconnected to theright of the valve seat 159F.

Thus, it can be seen that when the valve member 78F of the controldevice 29F is set for a broiling operation, the control signal can bedirected from the outlet 50F into the conduit 180 and pass through theopen valve seat 159F of the valve 155F to control the broil burner.

152F in the manner previously described because the ball valve member160F is not moved against the valve seat 159F until the temperature inthe oven exceeds an oven cleaning temperature.

When the valve member 78F of the device 29F is set for an oven cleaningoperation, the pneumatic signal from the outlet 50F is directed to theconduit 1811 to operate the broil burner 152F in the manner previouslydescribed while the conduit 181 is interconnected to the conduit 3115for the bake burner 151E. However, initially the oven is below apredetermined high temperature in the oven so that the ball valve memberF prevents any penumatic signal from being directed to the conduit 181and, thus, to the conduit 31E for the bake burner 151E so that the broilburner 152F is initially operated during the cleaning operation.However, when the temperature in the oven exceeds a predetermined hightemperature therein, the ball valve member 160F is moved intermediatethe valve seats 1581* and 159F so as to continuously operate the broilburner 152F and to also now turn on the bake burner 1515 so that bothburners 151E and 152F are utilized to raise the temperature to the selfcleaning temperature. However, as the temperature in the oven exceedsthe self cleaning temperature, the ball valve member 160F can close thevalve seat 159F and, thus, terminate the operation of the broil burner152F so that the ball valve member 161W will cycle the broil burner 152Fon and off while continuously maintaining the bake burner 151E on tomaintain a self cleaning temperature in the oven, the control device 29Facting as a high limit for a runaway condition during the oven cleaningoperation in the manner previously described for the control system 153.

Therefore, it can be seen that the control device 29 and main valvemember 24 of this invention can be utilized in various combinations toprovide different oven control systems as previously described.

While the valve means 24 previously described can have the configurationpreviously described in connection with FIG. 8, another embodimentthereof is generally indicated by the reference numeral 200 in FIGS. 11and 12 and will now be described.

As illustrated in FIGS. 11 and 12, the valve means 200 comprises ahousing means 201 carrying three flexible diaphragms 202, 203 and 204respectively defining chambers 2115, 206 and 207 with the housing means201. The diaphragm 204 carries a valve member 208 for opening andclosing a valve seat 209 which separates an inlet 210 from an outlet211. The diaphragm 2112 is interconnected to a tubular extension 212 ofthe diaphragm 203 by a spider-like member 213 which fluidlyinterconnects the open end 214 of the tubular extension 212 to theintermediate chamber 206. The diaphragm 203 carries a valve seat 215inside the tubular extension 212 which is adapted to be opened andclosed by a valve member 216 carried by the diaphragm 202 normally beingurged to a closed position by a compression spring 217.

The housing 201 has a tubular extension 218 extending into the valveseat 215 and defining a valve seat 219 at the open end thereof with thevalve seat 219 being interconnected to the inlet 210 by as passage 220.The inlet 210 is also interconnected by a passage 221 to an outlet 222that is adapted to be directed to a pilot burner for supplying acontinuous fuel flow thereto in the same manner as the passage 129 ofthe valve means 24.

The diaphragm 2113 cooperates with the housing to define a chamber 223that is interconnected by a passage 224 to the chamber 207 for thediaphragm 204. Thus, as long as the valve member 216 is held away fromthe valve seat 219 in the manner illustrated in FIG. 11, fuel from theinlet 210 is adapted to pass through the passage 220, open valve seat219, chamber 223 and passage 224 to the chamber 207 for the diaphragm204 so that the diaphragm 204 in combination with a compression spring225 will maintain the valve member 208 against the valve seat 209 in thesame manner as provided by the diaphragm 108 of the valve means 24.

The control pneumatic signal for operating the valve means 200 isadapted to enter an inlet passage 226 that is interconnected to theintermediate chamber 206 by an orifice cup 227 and directly into theactuating chamber 205 by a branch passage 228. The intermediate chamber206 is also interconnected to the pilot passage 221 by an orifice cup229.

Therefore, it can be seen that the valve means 200 operates in the samemanner as the valve means 24 previously described because when apneumatic signal is directed to the inlet 226, the same pressurizes thechamber 205 to move the diaphragm 202 downwardly and carry the diaphragm203 therewith so that the tu bular extension 218 of the housing 201 willbe engaged by the valve member 216 to close off the inlet 210 from theintermediate chamber 223 and further downward movement of the diaphragms202 and 203 cause the valve seat 215 to move away from the valve member216 in the manner illustrated in FIG. 12 so that the chamber 223 and,thus, the chamber 207 is vented to the chamber 206 which isinterconnected to the pilot passage 221 by the orifice cup 229 wherebythe pressure differential across the diaphragm 204 increases and theinlet pressure can cause the same to move to an open position asillustrated in FIG. 12 in the same manner as provided by the valve means24.

Therefore, it can be seen that modifications can be made in the variouscontrol devices of this invention with the operation thereof occurringin the same manner to accomplish the desired functions as previouslydescribed in connection with the oven control system.

Thus, not only does this invention provide improved oven controlsystems, but also this invention provides improved control devices forsuch control systems or the like.

While the form of the invention now preferred has been described asrequired by the statutes, variations can be made therein and all comingwithin the scope of the claims which follow.

What is claimed is:

l. A diaphragm operated valve construction comprising a housing meanshaving an inlet and an outlet interconnected together by a main valveseat, a diaphragm valve member carried by said housing means for openingand closing said main valve seat, said diaphragm valve member defining afirst chamber with said housing means, and a pair of diaphragms carriedby said housing means and defining second, third and fourth chamberstherewith, said housing means having means interconnecting said firstand second chambers together and having valve seat means forinterconnecting said inlet with said second chamber, one of saiddiaphragms carrying a movable valve member, the other of said diaphragmshaving a valve seat opening therein that interconnects said secondchamber with said third chamber, said movable valve member beingarranged for opening and closing said valve seat means while closing andopening said valve seat opening in said other of said diaphragms thatinterconnects said second chamber with said third chamber, said movablevalve member being disposed intermediate said pair of diaphragms andbeing movable therebetween, said diaphragms having means interconnectingthe same together to move in unison as said fourth chamber ispressurized or depressurized, said housing means having means ventingsaid third chamber to the exterior thereof and having passage means fordirecting pressure fluid to said fourth chamber.

2. A diaphragm operated valve construction comprising a housing meanshaving an inlet and an outlet interconnected together by a main valveseat, a diaphragm valve member carried by said housing means for openingand closing said main valve seat, said diaphragm valve member defining afirst chamber with said housing means, and a pair of diaphragms carriedby said housing means and defining second, third and fourth chamberstherewith, said housing means having means interconnecting said firstand second chambers togetherand having valve seat means forinterconnecting said inlet with said second chamber, one of saiddiaphragms carrying a movable valve member, the other of said diaphragmshaving a valve seat opening therein that interconnects said secondchamber with said third chamber, said movable valve member beingarranged for opening and closing said valve seat means while closing andopening said valve seat opening in said other of said diaphragms thatinterconnects said second chamber with said third chamber, saiddiaphragms having means interconnecting the same together to move inunison as said fourth chamber is pressurized or depressurized, saidhousing means having means venting said third chamber to the exteriorthereof and having passage means for directing pressure fluid to saidfourth chamber, said valve seat means being adapted to project into saidvalve seat opening to move said movable valve member away from saidvalve seat opening.

3. A diaphragm operated valve construction as set forth in claim 2wherein said housing means has bleed means for interconnecting saidfourth chamber to the exterior thereof.

4. A diaphragm operated valve construction as set forth in claim 2wherein said movable valve member is normally biased to close said valveseat opening in said other diaphragm.

5. A diaphragm operated valve construction comprising a housing meanshaving an inlet and an outlet interconnected together by a main valveseat, a diaphragm valve member carried by said housing means for openingand closing said main valve seat, said diaphragm valve member defining afirst chamber with said housing means, and a pair of diaphragms carriedby said housing means and defining second, third and fourth chamberstherewith, said housing means having means interconnecting said firstand second chambers together and having valve seat means forinterconnecting said inlet with said second chamber, one of saiddiaphragms carrying a movable valve member, the other of said diaphragmshaving a valve seat opening therein that interconnects said secondchamber with said third chamber, said movable valve member beingarranged for opening and closing said valve seat means while closing andopening said valve seat opening in said other of said diaphragms thatinterconnects said second chamber with said third chamber, saiddiaphragms having means interconnecting the same together to move inunison as said fourth chamber is pressurized or defourth chamber, saidmeans interconnecting said diapressurized, said housing means havingmeans venting phragms together comprising a tubular member having saidthird chamber to the exterior thereof and having said movable valvemember disposed therein.

passage means for directing pressure fluid to said

1. A diaphragm operated valve construction comprising a housing meanshaving an inlet and an outlet interconnected together by a main valveseat, a diaphragm valve member carried by said housing means for openingand closing said main valve seat, said diaphragm valve member defining afirst chamber with said housing means, and a pair of diaphragms carriedby said housing means and defininG second, third and fourth chamberstherewith, said housing means having means interconnecting said firstand second chambers together and having valve seat means forinterconnecting said inlet with said second chamber, one of saiddiaphragms carrying a movable valve member, the other of said diaphragmshaving a valve seat opening therein that interconnects said secondchamber with said third chamber, said movable valve member beingarranged for opening and closing said valve seat means while closing andopening said valve seat opening in said other of said diaphragms thatinterconnects said second chamber with said third chamber, said movablevalve member being disposed intermediate said pair of diaphragms andbeing movable therebetween, said diaphragms having means interconnectingthe same together to move in unison as said fourth chamber ispressurized or depressurized, said housing means having means ventingsaid third chamber to the exterior thereof and having passage means fordirecting pressure fluid to said fourth chamber.
 2. A diaphragm operatedvalve construction comprising a housing means having an inlet and anoutlet interconnected together by a main valve seat, a diaphragm valvemember carried by said housing means for opening and closing said mainvalve seat, said diaphragm valve member defining a first chamber withsaid housing means, and a pair of diaphragms carried by said housingmeans and defining second, third and fourth chambers therewith, saidhousing means having means interconnecting said first and secondchambers together and having valve seat means for interconnecting saidinlet with said second chamber, one of said diaphragms carrying amovable valve member, the other of said diaphragms having a valve seatopening therein that interconnects said second chamber with said thirdchamber, said movable valve member being arranged for opening andclosing said valve seat means while closing and opening said valve seatopening in said other of said diaphragms that interconnects said secondchamber with said third chamber, said diaphragms having meansinterconnecting the same together to move in unison as said fourthchamber is pressurized or depressurized, said housing means having meansventing said third chamber to the exterior thereof and having passagemeans for directing pressure fluid to said fourth chamber, said valveseat means being adapted to project into said valve seat opening to movesaid movable valve member away from said valve seat opening.
 3. Adiaphragm operated valve construction as set forth in claim 2 whereinsaid housing means has bleed means for interconnecting said fourthchamber to the exterior thereof.
 4. A diaphragm operated valveconstruction as set forth in claim 2 wherein said movable valve memberis normally biased to close said valve seat opening in said otherdiaphragm.
 5. A diaphragm operated valve construction comprising ahousing means having an inlet and an outlet interconnected together by amain valve seat, a diaphragm valve member carried by said housing meansfor opening and closing said main valve seat, said diaphragm valvemember defining a first chamber with said housing means, and a pair ofdiaphragms carried by said housing means and defining second, third andfourth chambers therewith, said housing means having meansinterconnecting said first and second chambers together and having valveseat means for interconnecting said inlet with said second chamber, oneof said diaphragms carrying a movable valve member, the other of saiddiaphragms having a valve seat opening therein that interconnects saidsecond chamber with said third chamber, said movable valve member beingarranged for opening and closing said valve seat means while closing andopening said valve seat opening in said other of said diaphragms thatinterconnects said second chamber with said third chamber, saiddiaphragms having means interconnecting the same together to move inunison as said fourth chamber is pressurized or depressurized, saidhousing means having means venting said third chamber to the exteriorthereof and having passage means for directing pressure fluid to saidfourth chamber, said means interconnecting said diaphragms togethercomprising a tubular member having said movable valve member disposedtherein.